1. Field of the Invention
The invention relates to mechanisms for adjusting and locking the position of tiltable steering wheels on vehicles such as lawn and garden tractors.
2. Description of the Related Art
It is known to provide vehicles with tilt steering mechanisms to allow the operator to adjust the inclination of the steering column. These mechanisms allow the steering wheel to be shifted upwardly to allow the operator more room to mount and dismount the vehicle. They also allow the steering wheel to be adjusted to the operating position most comfortable for a particular operator. Typical mechanical steering mechanisms provide a universal joint in the column that accommodates pivoting of the upper portion of the column. Hydraulic steering mechanisms, on the other hand, often provide a steering wheel mounted on a short pivotable steering column, and provide a flexible hydraulic coupling between the tiltable column and the steerable ground engaging wheels.
Conventional tilt mechanisms also provide assemblies that lock the steering column in a desired operating position. These locking mechanisms can be released by an operator so that the steering column and steering wheel can be adjusted to a different position.
Tilt lock controls found on automobiles are typically located on the steering column between the steering wheel and the dash. The control is typically a lever that is coupled to a series of cams, linkages and levers within the steering column. These linkages extend down the column from the control lever to the locking mechanism. The control lever is actuated to release the locking mechanism via the linkage. The locking mechanisms typically provide a toothed assembly that engages an element or another toothed assembly to lock the column in position.
Typical tilt steering wheel mechanisms on automobiles are relatively complicated due to the large number of parts utilized in the linkage that extends between the control lever and the locking mechanism and within the steering column. Therefore, these mechanisms are relatively costly to manufacture and assemble.
The placement of the control lever on the column between the steering wheel and the dashboard may interfere with the operation and view of other instruments located on the dash near the steering wheel. Therefore, the steering wheels of automobiles are positioned a relatively large distance away from the dash in order to make room for the control lever. These mechanisms are therefore not well suited for use on lawn and garden tractors, which usually have a short distance between the steering wheel and dash due to limited space in the operator station. Also, lawn and garden tractors often provide gauges and controls on the dash near the steering column, such that positioning a tilt steer control lever on the steering column may overcrowd the instrument panel and make it difficult to reach and manipulate the various controls on the dash.
In addition, tilt steering wheel mechanisms found on automobiles are typically not adapted for sealing the mechanisms from exposure to the elements, since the operator stations and tilt steering mechanisms of automobiles are usually enclosed within cabs. Therefore, many automotive tilt steering mechanisms are not readily adaptable for use on lawn and garden tractors, which typically expose operator stations to the elements.
Tractors and other off-road vehicles have provided tilt steering mechanisms. Many such vehicles provide only a short distance between the steering wheel and dash, or provide controls or gauges on the dash near the column, and therefore do not provide a tilt control lever on the steering column. Rather, many of these vehicles locate the tilt control on a console near the operator's legs. Many such controls must be pulled by the operator in order to release the steering column lock. Therefore, an operator wearing gloves may find it difficult to grasp the control and release the steering column position lock.
Off-road vehicles often provide assemblies for enclosing or sealing the tilting mechanisms from exposure to the elements. However, since the steering columns are shiftable to a variety of different positions, many such enclosures do not effectively exclude the elements from the internal workings of the steering mechanism. The enclosures that do effectively seal the steering column mechanism are often costly to manufacture and assemble.
Tilt steering mechanisms used on lawn and garden tractors and other off-road vehicle's typically provide a linkage between the tilt control knob and the internal locking mechanism. Like the automobile tilt mechanisms, the use of a linkage having many parts complicates the manufacture of the assembly and makes the mechanism more costly.
Both automobiles and off-road vehicles provide mechanisms for biasing the tilt mechanism toward a locked position. Springs are often used as the main component in biasing mechanisms, and are held in place by such means as cotter pins positioned within drilled holes, washers that abut upraised portions in rods, or snap rings held within grooves. These biasing mechanisms are typically comprised of a plurality of parts that are relatively time consuming and costly to assemble.
Therefore, it would be advantageous to provide a pivotable steering wheel mechanism for use with an open-cabbed vehicle that utilizes a small number of parts and is relatively inexpensive to manufacture. Also, it would be advantageous for such a mechanism to have its control means located below the vehicle dash near the operator's legs. It would be advantageous for the control for this mechanism to be pushable by the operator such that the release of the locking device is made easy in a variety of conditions, for example, when the operator's hand is gloved. It would also be advantageous for such a mechanism to provide an inexpensive and effective enclosure that will effectively seal the mechanism from the surrounding weather conditions regardless of the steering column's pivoted position. It would be desirable to provide a simple and effective mechanism for coupling a biasing spring to a member that is relatively simple and easy to assemble.